comparing string values

[nikos]

Hi,
I am very new to oracle and have some problem figuring out how to compare two string columns in different tables for non-similarity.
suppose i have column a in table 1 as t1.column_a and column b in table 2 as t2.column_b.
i want to see unique entries that are not equal to each other....if t1.column_a has some entries that are not present in t2.column_b and if t2.column_b has some entries not present in t1.column_a.
Thanks a lot for any input.

[debasisdas]

Try using Join in sql query.